Problem with scaling uv's to tile textures at the right size
I think what you might be really looking for is using a different set of UVs to bake and a different set to map your source texture. This is a cleaner solution that will allow you more flexibility later on, and will also work nicely if you want to use texture atlases (bake many objects to one large texture).

This way you can scale the brick UVs without affecting the UVs used for baking. It's in Properties panel > Object Data tab > UV Maps > [+] button. You can have one UV set for the bricks ("brick uvs") and one for baking ("baking uvs"). Set the "baking uvs" as default for rendering (camera icon). 

Then in Node Editor, instead of using the Input > Texture Coordinate node's UV output as you are now (this only uses one default UV layout) you can choose Input > UV Map, this lets you choose which UV layout you want to get your UVs from - pick "brick uvs" as input for your texture.

If you do this correctly you should be able to freely adjust the UVs for the bricks without affecting the UVs you use for baking.

Update: see this file for an example http://www.pasteall.org/blend/38727